Container cap, cap liner, and method of applying liners to container caps



2,073,415 CONTAINER CAP, CAP LINER, AND METHOD or APPLYING LINERs ToCONTAINER CAPs E. M, ENKUR March 9, 1937.

Filed Oct. 5, 1934 3Min/Wto@ Patented Mar. 9, 1937 PATENT oFFicE --jCONTAINER CAP, CAP LnvER, ANDME'rnoD oF ArrLrmG LINERS -To ooN'rAnmalCAPS Edward M. Enkur, Baltimore, Md., asslgnor to Crown Cork & SealCompany, Inc., Baltimore, Md., a corporation of New York ApplicationOctober 5,l 1934, Serial No. 747,045

2 Claims.

` caps are usually provided with a liner. The liner l ordinarilyincludesan impervious facing member which bears directly upon thecontainer :mouth and which is of such material that it will no t affector be affected by the substance placed in the container. The lfacingmember is usually bonded to a backing member, the latter being ofresilient material, so that when the cap is positioned upon thecontainer, any depressions or protuberances upon the surface of themouth or lip of the container will be compensated for o and a properseal maintained. The bonding between the facing and the backing isusually obtained by application of an adhesiveof suitable nature, but,in many instances, the. adhesive penetrates the backing member,decreasing the resiliency of the latter and thereby reducing itseffectiveness. i 'An important object on the present invention is toprovide a liner for container caps which will be completely resilientand in which the facing and backing members are secured together by abonding material which is extremely effective forbonding purposes andwhich also increases the resiliency and sealing effectiveness of theliner. It is highly desirable to have the liner so arranged wlth respectto the cap that it cannotA fall from the latter, either before the caphas been placed upon a container or after it has been removed from thecontainer by the consumer.

40 If caps are of a type provided with an unsecured liner, each cap mustbe inspected before it is placed upon the container, to make certainthat the liner is in position. Also, if the liner is not secured in thecap and falls from the latter when 'the container is opened by theconsumer, the

' container will not be properly re-sealed and the contents of thecontainer may be adected.

. When the skirt of the cap is provided with inwardly projectingthreads, lugs, or other retaining means to hold it upon a container, itis not practicable to have the liner of a diameter sufciently large tocontact with the largest inner diameter of the cap skirt, because theliner must be inserted in the cap past the inwardly proiecting'retainingmeans. Also, since caps provided with such retaining means are usuallyrotated with respect to the container mouth to secure them upon'thecontainer, it is not feasible to endeavor to retain the liner in the.cap by adhesive applied between the liner backing and the undersurfaceof the cap top because rotation of the cap relative to the containermouth may break the adhesive bond between the liner and cap, permittingthe liner to .fall'from the cap when the latter is removed from thecontainer. For this reason,'in order to prevent the liner from fallingfrom the cap, it is ordinarily necessary to design liners for such capsin some special form whereby the liner will be held Withinthe cap andprevented from moving past the threads, lugs or'other retaining meansand falling from the cap. The provision of means to hold the linerwithin the cap ordinarily increases the cost of manufacture of theliner.

Another important object of the present invention is to provide a linedcontainer cap and a method of applying a linerthereto, whereby thelatter will be securely held within the cap and the sealingqualitiesofthe cap improved, the arrangement of the cap and the method by which itis lined being such that the cost of the cap will not be increased.

The cap of the present invention may be broadly described as providedwith a liner having a body of less diameter than the greatest diameterof the cap skirt, and which liner, after insertion in the cap, issubjected to either pressure or heat, or both, over a predetermined areathereof to cause a portion of the liner, preferably the 'bondingmaterial, to contact with the cap skirt to retain the liner in the cap.

lIn the manufacture of crown caps, it is quite usual to positlona linerwithin a cap. and to then subject the liner to heat and pressure.However, the purposeof applying heat and pressure to the liner of such acap is to cause adhesive arranged between the liner and the top .of thecap to be so affected as to securely hold the liner in the cap.Furthermore, the liners used in crown caps, even as originally insertedin the cap, may 45 be, and ordinarily are, of the same diameter as theinner diameter'of the skirt, because the skirts of such caps are notprovided with any inwardly projecting retaining means. For this reason,although the liner may be slightly increased in diameter by the pressureapplied thereto, the pressure is not applied for the purpose of causingthe liner to contact with the skirt of the Gap but, as stated above,merely to insure that 55 the adhesive will properly hold the liner tothe cap.

Other objects and advantages of the inventionA will be apparent from thefollowing drawing, wherein:

Figure 1 is a central vertical sectional view through a cap, showing theform of the liner when initially positioned in the cap.

Figure 2 is a central vertical sectional view of the cap of the presentinvention, illustrating the method whereby the liner is secured in thecap.

Figure 3 is a vertical sectional view showing the mouth of a containerhaving the cap of the present invention applied thereto, and

Figure 4 is a view of the liner device of the present invention, withportions broken away.

'Ihe numeral I0 designates a cap including a top II and a skirt I2 Theskirt is provided with threads I3 but it will be understood that,instead,

lugs or any other retaining means may be pro- Cil vided uponl the skirt,the nature of the retaining means forming no part of the presentinvention. The top- II ofthe cap may be provided with an annular grooveadjacent its peripheral edge which forms a downwardly projectingshoulder I4 upon pulp board, heavy paper stock or any fairly stiffmaterial which is sufficiently resilient to assist in the provision of aproper seal between the container and the cap. 'I'he facing I8 may beformed of various materials, according to the nature'of the substance tobe placed in the container. For example, it may be of metal foil or mayhave its lower surface coated with metal foil or it may be of paperstock having a varnish or other protective coating applied thereto.

The plastic material forming the layer I1 is preferably material of suchnature that it will flow upon the application of heat or pressurethereto and is more resilient than the backing I6. The material I1should also have some adhesive' qualities in order to hold together thebacking I6 and the facing I8. It is further desirable that the materialI1 have some frictional Cfr qualities, the latter for a purpose to behereinafter set forth. I find that gutta percha or india rubber, meetsall of these requirements; such material being sufficiently tacky tohold together as shown in Figure 1, the diameter of the liner being lessthan the greatest diameter of the cap skirt so that it may. be freelysprung or moved past the threads, lugs or other retaining means I3provided upon the skirt of the cap, as is the usual practice. A

As shown in Figure 2, pressure is then applied to the faced surface ofthe liner by means of a die such as 20. .The die 20 includes an annularshoulder or ridge 2| adjacent the edge thereof,

y the inner edge of the shoulder preferably being inclined and its outeredge being slightly rounded,'all so that the shoulder will generallyconform to the outline of the mouth of the container upon which the capis to be used. If desired, the die may be heated by a burner such as 23,which, when the die is raised, will direct a flame against the side ofthe die at the lower portion thereof. However, the die may be heated inany other Well known manner.

'I'he die 20 is applied to the liner with such force that the pressureof the die or, if the die is heated, the pressure. and heat of the die,will cause the portion of the bonding material I1 adjacent the outeredge of the liner to flow outwardly from between the backing I6 andfacing I8 to form a projecting edge 24 which will contact with the innerwall of the skirt I2 of the cap. It will be noted that because thecentral portion of the die 2U is recessed, little if any pressure willbe applied to the central portion of the liner, the pressure and heat,or whichever is depended upon to cause the material I1 to flow, beingsufllciently localized that the only portion' of the bonding layer whichwill be extruded or forced outwardly past the body of the liner is thatwhich would ordinarily be substantially beneath the cap shoulder I4, andhence comprise the annular area against which the mouth of the containerwould subsequently bear. In other words, the application of the die 20to the liner I5 will result in a groove 3| about the undersurface'of theliner into which the mouth of the container may project. and, as shownin Figure 3, the side walls of this groove will naturally contact withthe, edges of the container mouth to form a more vsecure seal betweenthe container mouth and liner.

'Ihe outward extrusion or projection of a portion of the bondingmaterial into contact with the skirt I2 of the cap will prevent theliner l5 from falling from the cap, since the bonding material hassufficiently high frictional or adhesive qualities to firmly grip theskirt. It will be understood that the original thickness of the layer ofbonding material I1 is such that sufficient material may move outwardlyinto contact with the cap skirt, preferably without entirely removingall of the bonding material against which the die shoulder 2| appliespressure.

It will be understood that the invention is not limited to the detailsand use shown in the d rawing and that the phraseology employed in thespecification is for the purpose of description and not of limitation.

1. In combination, a container cap and a liner, said cap including a topand a skirt provided with inwardly projecting retaining means by whichthe cap may be secured upon a container, and said liner including a fiatbacking layer having a body diameter greater than the inner diameter ofthe retaining means and which is formed of relatively stiif butresilient material so that it may' be inserted in the cap past theretaining means without distortion from its normal form, said linerfurther including a portion having substantial adhesive qualities andadapted to be forced past the edge of said stiff layer of the liner uponthe application of pressure thereto so as to engage the cap skirt andhold the liner against movement relative to the cap.

2. In combination, a container cap and a liner, said cap including a topand a skirt provided with inwardly projecting retaining means by face ofsaid backing layer, said last-named layer having only suicient thicknessso that when pressure is applied to the portion thereof adapted `to beopposite the edge of a container, the material extruded from thatportion will be sumcient to rmly engage the cap skirt to hold the lineragainst movement relative to the cap.

'EDWARD M. nNxUa.

